Geometrical instrument



i July 27,1926.

A. JEFFERS GEOMETRICAL INSTRUMERI'YIi Filed 0019513 1923 lill Patented July Z7, 1926i.

Aueus'r JEFFERS, or PHiLAnELPHIA, PENNSYLVANIA.'

GEOMETRICAL INSTRUMENT.

Application filed october 18, 1923. Serial No. 668,329.

This invention relates to certain new and useful improvements in geon'ietrical instruments and has particular reference to instruments of that kind embodying a plurality ofV relatively movable members adapted to be set in different relations for performing different kinds of work.

. The primary object of the invention is to provide a geometrical instrument of the above kind which may be readily changed for use as a compass, scriber, bevel, or square.

Another object is to provide a geometrical instrument having the above characteristics embodied in a simple and durable construction capable of being` readily and easily placed into practical use as well as cheaply and easily manufactured.

Still another object of the invention is to provide a combination geometrical instrument of the above kind embodying adjustable leg members whereby a compass of the desired size may be readily had and wherein one of the adjustable leg members is adapted to be reversely employed for acting as a point of the compass or as a scriber of the trammel.

Another object to generally simplify and improve devices of the above kind, whereby the same may meet with all of the requirements for a successful commercial use.

Other objects will appear as the nature of the invention is better understood, and the same consists in the novel form, combination, and arrangement of parts hereinafter more fully described, shown in the accompanying drawings. and claimed.

In the drawing, wherein like reference characters indicate corresponding parts throughout the several viewst- Figure 1 is a side elevational View showing the instrument in position for use as a scriber.

Figure 2 is a View similar to Figure 1, with the parts adjusted to be employed as a compass.

Figure 3 is a transverse sectional view, taken on the line 33 of Figure 2.

Figure 4 is a view similar to Figure 3, taken on the line 4 4 of Figure 2, and

Figure 5 is a transverse section taken on line 5-5 lof Fig. 9..

Referring more in detail to the drawing, the present invention includes a pair of relatively elongated plates 5 and 6, the latter of which is provided with a longitudinal elongate-d slot 7 through which loosely passes a bolt having a wing nut 8 threaded thereon, which bolt also passes through one end portion of the other plate 5 whereby said plates are pivotally and slidably connected.

The plates 5 and 6 each has one of its longitudinal edge portions formed of arcuate cross section to provide a channel 9, and straight bar 10 is longitudinally slidable in the channel 9 of the plate 5 while another member 11 is longitudinally sli'dable in the channel 9 of the plate 6. The members or bars 10 and 11 are engaged in the channels 9, by means of set screws 12 which pass through openings in the arcuate flanges 20. These screws 12 not only serve to hold the bars when in the channels 9 and integral flanges Q0 formed on the edges of the channels, but will maintain the same in any longitudinal adjusted position.

The bar 11 is of straight form for a major portion of its length and pointed at one end while the other end thereof is directed laterally to provi-de a socket 13 for retaining reception of a scribing pencil 14.

By positioning the plates 5 and 6 at right angles to each other with the plate 5 eX- tending laterally from one end of the plate 6 as shown in Figure 1, said plates cooperate to provide a square, at which time the members 10 and 11 may be removed. By attaching the bar 11 to the plate 6 so that the scribing pencil retaining socket 18 thereof is outermost as shown in Figure 1, a scriber is provided, and by reversing the position of the bar 11 and attaching the bar 10 to the plate 5 and then adjusting the plates 5 and 6 into closely diverging relation as shown in Figure 2, a compass is formed. The size of this compass may be varied by adjusting the bars or rods 10 and 11 longitudinally relative to the plates 5 and 6. Also, it is obvious that the guide plate 5 may be adjusted toward and away from the scribing pencil. 14 when the parts are positioned as shown in Figure 1, for an obvious purpose.

The plates 5 and 6 may be formed from sheet metal by a simple stamping and shaping operation, so that the device may be comparatively cheaply manufactured.

From the above description, the construction and operation, as well as the advantages of the present invention will be readily understood and appreciated by those skilled in the f art, and-.minor-` ehangesunay be made Without departing'rom the spirit' andvvscope of the invention as claimed.

What I claim asnevv. is.:-

A geometrical" instrument comprising a pair of pivotally connected elongatedzplates, I

each plate being provided at one of its longitudinal edges Wilt'hfa curvedv pon-tion, said curved portion being arcuate in trans- U verse cross section,: and the are ffbeing ,11e/ss `portionv vand-'the flange and adapted to be held in place by the set screw.

In testimony -Whereof I afx my signature.

AAIITGSI JEFFERSI. 

